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Contract¶

The model's own time window — the historical scope its runs may target. Bollhav uses begin and end to decide what range to walk in reload / backfill modes. In latest mode they're ignored — latest reads from now().

from bollhav.model import Contract

Model(contract=Contract(begin=..., end=...), ...)

Not the same as an upstream contract. This Contract is this model's own time bounds. A downstream's gating policy on an upstream is a separate thing — an UpstreamContract level. Both ride a contract= parameter (one on Model, one on Source), but they're different types.

Only a TEMPORAL model has a time axis, so only a temporal model carries a begin/end. A TIMELESS model has no time to reference — giving one a begin/end raises at validation.

A temporal model needn't be batched. With batching, the window is split into chunks (one state row per window). Without batching, a temporal model with a closed begin/end loads that whole range in one run and records it as a single state row spanning [begin, end] — so a downstream can still gate an ENCAPSULATE contract against it (its window must fall inside the range).

begin¶

Type: datetime · Default: None

Window start. Must be UTC-aware (tzinfo=timezone.utc); naive datetimes raise at validation. In reload/backfill it's where the walk starts.

end¶

Type: datetime · Default: None

Window end. Must be UTC-aware. When None, a reload walks up to the latest complete tick.

Contract¶

begin¶

end¶

See also¶